1. Field of the Invention
This invention relates to a display apparatus and more particularly to a display apparatus having a unidirectionally elongated, rotatable display screen.
2. Description of the Related Art
The majority of information processing systems have a display apparatus utilizing a CRT, LCD or the like. The display apparatus has a display screen which is typically rectangular with corners rounded. With regard to display of information on the display screen, either a vertically elongated display or a laterally elongated display is preferred case by case. Such languages as Japanese, Chinese and Korean allow both vertical writing and lateral writing notations and they may sometimes be used properly to comply with the form, vertical elongation or lateral elongation, of the display screen.
Frequently, the information processing system incorporates the display apparatus and a print-out device in combination. In the case where information is edited on the display screen and thereafter printed by means of the print-out device, it is desirable that the display screen match the form of the printing paper.
When pictures are displayed on the laterally elongated screen of the CRT display apparatus and are desired to be printed on vertically elongated printing paper, characters are required to be rotated through 90.degree., rearranged and then outputted. A method proposed to this end, however, needs a memory of extremely large capacity for storage of image data as well as much processing time before outputting when executing the rotation and rearrangement by using software. Accordingly, another method has been proposed (Japanese Patent Publication No. 57-60671) wherein one frame is divided into many square regions and the rotation and rearrangement is effected for individual square regions. The division of the frame permits a reduction in memory capacity necessary for processing and a reduction in processing time. In this latter proposal, the memory image matrix is divided into a smaller matrix of more cells each having, for example, 8.times.8 bits. Laterally arranged cells of the small matrix are stored in laterally arranged registers and then transferred to and stored in vertically arranged registers, thereby completing rotation of image data.
In still another proposal, the display screen of the display apparatus is made rotatable to match the printing paper. The display apparatus may be used properly such that its display screen is held in a position of lateral elongation when the printing paper is used in a position of lateral elongation or its display screen is held in a position of vertical elongation when the printing paper is used in a position of vertical elongation.